Electrochemical detection of natural estrogens using a graphene/ordered mesoporous carbon modified carbon paste electrode
A novel electrochemical biosensor based on an electrodeposited graphene/ordered mesoporous carbon composite modified carbon paste electrode (GR/OMC/CPE) was prepared for the quantitative determination of natural estrogens by square wave voltammetry (SWV). The electrodeposited GR/OMC composite modified electrode was prepared with a CPE by cyclically sweeping in the potential range from −0.8 to +2.4 V at a scan rate of 100 mV s−1 in 0.1 mg mL−1 OMC and GR, respectively. The morphology of the GR/OMC composite was characterized by scanning electron microscopy. The electrochemical behaviors of estrogens at the GR/OMC/CPE were investigated by cyclic voltammetry, and the results showed that the GR/OMC/CPE exhibited excellent electrocatalytic activity toward the oxidation of natural estrogens involving estrone, estradiol, and estriol. SWV was used for the quantitative determination of estrogens. Under the optimal conditions, the current response was linearly proportional to the concentration of estrogens in the range from 5.0 × 10−9 to 2.0 × 10−6 mol L−1, with a low detection limit of 2.0 × 10−9 mol L−1 (S/N = 3). The proposed sensor was successfully applied to analyze estrogen levels in female serum samples.